My cheap and cheezy method has been to use aluminum foil tape on the back side (rather than painter's tape), cut it out in circles a little bigger than the hole, and stick it on the underside. Then I'll use the black RTV on the other side. I just leave the aluminum foil tape in place and it leaves some semblance of a backing there.
I've had to chisel out fiberglass that people have added for stuff like this in the past, and I'm not a fan. If you're planning on just leaving it - that's probably ok just sucks for the next person if they want to put metal back in. But I prefer to just do something like this as a temporary repair, then go back in later to weld it shut. Or are you saying you just use the fiberglass sheet as a backing for the por15 with no epoxy?
@ cut to size, paint regular por15 on area, adhere fiberglass sheet, then paint another por15 coat. Definitely would be unfun to remove, but just use wisely
POR-15 Patch works great on RUST. Can't stress this enough it loves rust don't use it on clean metal in fact don't use any POR-15 product on clean or even mildly rusted metal it will peel off in a few years. For rust paint use Rust Bullet it's not UV reactive and adheres to rusted or clean metal.
I drove the car for a few hours today - and I can confirm that this stuff works GREAT at sealing out the exhaust odors from cruising on the highway.
My cheap and cheezy method has been to use aluminum foil tape on the back side (rather than painter's tape), cut it out in circles a little bigger than the hole, and stick it on the underside. Then I'll use the black RTV on the other side. I just leave the aluminum foil tape in place and it leaves some semblance of a backing there.
Ooh that's a good one! I've had mixed results with the black RTV on my cars, but if it works for you that's awesome!
Fiberglass sheet and por15 works great. Krud Kutter beforehand and parts cleaner spray before paint.
I've had to chisel out fiberglass that people have added for stuff like this in the past, and I'm not a fan. If you're planning on just leaving it - that's probably ok just sucks for the next person if they want to put metal back in. But I prefer to just do something like this as a temporary repair, then go back in later to weld it shut.
Or are you saying you just use the fiberglass sheet as a backing for the por15 with no epoxy?
@ cut to size, paint regular por15 on area, adhere fiberglass sheet, then paint another por15 coat. Definitely would be unfun to remove, but just use wisely
POR-15 Patch works great on RUST. Can't stress this enough it loves rust don't use it on clean metal in fact don't use any POR-15 product on clean or even mildly rusted metal it will peel off in a few years. For rust paint use Rust Bullet it's not UV reactive and adheres to rusted or clean metal.
That's a really good point. For normal Por-15 paint stuff there's always a bunch of prep work to do to make it stick.